Text Diff Checker

What is Text Diff?

The Text Diff Checker compares two blocks of text and highlights exactly what was added, removed or changed — at line or word granularity — using a Myers-style diff algorithm (the same class of algorithm underlying git diff).

How it works

Both inputs are diffed client-side with the `diff` library. Line mode shows whole lines with +/− markers; word mode re-diffs changed hunks word-by-word for fine-grained highlighting. Removals are shown with strikethrough, additions with a highlight, and a +/−/~ summary counts the changes.

1. Paste both versions. Paste the original text on the left and the modified text on the right.
2. Choose granularity. Line-level shows whole-line changes; word-level highlights the exact words that changed inside a line.
3. Read the diff. The +/−/~ counters summarize the change, and each changed line is highlighted with markers that don't rely on color alone.

Examples

Document revision

Compare two drafts of a contract or article to see exactly which sentences were edited, added or removed.

Config comparison

Paste two versions of a config file to spot the changed settings without a version-control client.

Common mistakes

Whitespace-only changes

Line-level diff treats trailing whitespace changes as real changes. If your files differ only in formatting, use a formatter first.

Very large documents

Diffs of tens of thousands of lines can be slow on the main thread — for enormous files, split the input.

Alternatives

JSON Diff

Structural diff for JSON documents — ignores whitespace and key order.

CSV Diff

Row-aware comparison of CSV files matched by a key column.

Frequently asked questions